use strict;
use warnings;

# use Data::Dumper;

my %hash = ();

my @array1 = qw(a b c d e);
my @array2 = qw(1 2 3 4 5);

push @{$hash{col1}}, @array1;
push @{$hash{col2}}, @array2;

# print Dumper(%hash);

# Result should look like this:
# col1,col2,
# a,1
# b,2
# c,3
# d,4
# e,5